"My wife was in bed relaxing when a very attentive nurse at Cedars-Sinai ... was checking him out and heard a murmur in his heart, which is common with newborn babies," Kimmel explained. "But she also noticed he was a bit purple, which is not common."

In the hours that followed, the parents learned Billy had "a hole in the wall of the left and right side of his heart" that prevented him from getting enough oxygen to his blood. It would require multiple surgeries to fix.

The 49-year-old father of four revealed that the first of Billy's procedures was behind him. The others will come when he's older.

The surgeon "went in there with a scalpel and did some kind of magic that I couldn’t even begin to explain," he said.

Kimmel shared a photo of his baby boy, and it's easy to see why, ultimately, his tears were happy ones.

Kimmel's newborn baby, William JohnJimmy Kimmel Live / YouTube

Kimmel joked, “Poor kid, not only did he get a bad heart, he got my face."